Method of manufacturing a wiring substrate

1. A method of manufacturing a wiring substrate which includes a substrate which has a first surface and a second surface, a first insulating layer which is stacked on the first surface of the substrate, a pad electrode which is formed on the first insulating layer, and a through electrode which passes through the substrate and the first insulating layer, comprising: forming a through hole which passes through the substrate toward the pad electrode from the second surface of the substrate, the step of forming the through hole including: forming a first concave portion in the substrate that extends from the second surface to the first insulating layer without passing through the first insulating layer; forming a second insulating layer at least within the first concave portion; and forming a second concave portion through the second insulating layer and the first insulating layer to expose a surface of the pad electrode, the second concave portion being formed within the first concave portion; and filling the first concave portion and the second concave portion with a conductive body or forming the conductive body to coat inner walls of the first concave portion and the second concave portion, and forming the through electrode such that the through electrode is connected to the pad electrode.

2. The method according to claim 1 , wherein the first insulating layer and the second insulating layer are formed of different materials.

3. The method according to claim 2 , wherein the first insulating layer is removed by dry etching when the second concave portion is formed.